Sinensetin, yet another anabolic substance from citrus
It is becoming increasingly apparent that extracts from oranges or other citrus fruits have muscle-building properties. We previously wrote about the anabolic effect of the liminoids obacunone and nomilin, which cause muscle growth by interacting with the bile acid receptor TGR5. Today we are bothering you with yet another substance with anabolic properties in citrus. Its name is sinensetin.
Sinensetin is a flavonoid with no less than 5 methoxy groups. There are more of those flavonoids in citrus, such as nobiletin and tangeretin. These substances probably have a greater bioavailability than other flavonoids without methoxy groups.

South Korean researchers at Gyeongsang National University did in vitro experiments with muscle tissue from young rats of 6 weeks old and tissues from young-aged rats of one year. The older test animals had significantly less muscle tissue than the young test animals.

The researchers extracted young muscle cells from muscle tissues and allowed them to form muscle fibers. The cells from the young rats formed larger fibers - to put it more precisely: myotubes - than the cells from the older rats, but this difference disappeared when the researchers exposed the older muscle cells to sinensetin. You can see this below.

The figure above shows how sinsensetin stimulates muscle development in older muscle cells in vitro. The poly methoxy flavonoid increased the production of the anabolic signalling molecules myoD and myogenin.The Koreans suspect that sinsentin suppresses the production of inflammatory proteins in older muscle tissue. As a result, the muscle cells would be able to produce more anabolic signalling molecules.
"These findings suggest that sinensetin treatment may have a potent effect on the prevention of age-related sarcopenia by increasing the protein levels myoD and myogenin and further detailed study will help to validate the involvement of inflammation", write the Koreans.

"Furthermore, these data provided basic evidence on the effect of sinensetin on sarcopenia and thus it may be beneficial to produce potent drug against the conditions of muscle loss."
BMC Complement Altern Med. 2019;19(1):287.